Many objects have intrinsic value or have value because they provide access to other valuable objects. For instance, jewelry and coins have inherent intrinsic value while keys, such as keys to vehicles, have value because they provide access to other valuable objects, namely automobiles and trucks. Further, access to and control of some items, such as narcotics for example, needs to be monitored, tracked, and controlled to assure against unauthorized access or assure that proper and appropriate accesses catalogued. There is a serious need to be able to track, catalogue access to, and control such objects in a way that is reliable, simple to implement, and virtually tamper proof.
In the past, a variety of systems have been implemented to track and control objects. In the case of keys in an automobile dealership, for example, pegboards have been used to keep track of the keys as sales persons, maintenance personnel, and others remove keys for access to vehicles. Generally, sign out sheets are used to log the check-in and checkout of such keys. Obviously, such a manual system of tracking has numerous shortcomings due in large part to the very real potential of human error and forgetfulness in carrying out the sign-in and sign-out procedures.
More recently, automated computer controlled key tracking systems have been implemented for tracking, for example, vehicle keys at car lots and keys to the apartments of apartment complexes. One such system particularly applicable to the present invention is the key tracking system disclosed and claimed in my U.S. Pat. No. 5,801,628 the disclosure of which is hereby incorporated fully by reference. In the disclosed system, referred to herein as the "Key Track" system, keys to a vehicle are attached with a rivet or the like to a thin plastic key tag or card having a depending tongue. The tongue carries a small button shaped electronic touch memory device, which electronically stores a unique code. The tongues of the key tags are configured to be insertable in an array of slots formed in a top panel within a storage drawer. A printed circuit backplane is disposed beneath the top panel and is provided with a plurality of pairs of metal contacts, each pair of contacts being aligned with a corresponding one of the slots in the top panel. When the tongue of a key card is inserted in a selected one of the slots, its touch memory device is engaged by the corresponding pair of contacts.
A computer or microprocessor or microcontroller based controller is electronically coupled through a communications matrix to the contacts on the backplane and periodically polls each pair of contacts, preferably several times per second, to determine the presence or absence of a touch memory device and thus which slots contain key cards and which do not. More specifically, if no information is received from a particular pair of contacts when polled, it is determined that the slot corresponding to the pair of contacts is empty. When a slot contains a key card, the touch memory device of the card responds to the poll by transmitting its unique code, from which the identity of the particular key attached to the card can be determined through a table lookup. In this way, the absence or presence and location in the storage drawer of key cards and their associated keys can be noted by the controller each time the array of contacts are polled. If a card present in a slot on a prior polling is absent on a subsequent polling, then the controller notes that the card and its key have been removed from the storage drawer. Conversely, if a key card is detected in a previously empty slot, the controller notes that the card and its key have been replaced in the storage drawer. The removal and replacement of keys is therefore continuously monitored.
An access feature requires an authorized user such as a sales person to enter an ID code to unlock and access the storage drawer. When the history of removal and replacement of key cards and their keys is combined with other information, such as the time at which cards are removed and replaced and the identities of the persons who accessed the drawer and times of access, access to the keys in the drawer can be controlled and a detailed tracking log can be created. This Key Track system greatly decreases instances of lost keys, reduces the time required to find checked-out keys, and generally provides automatic tracking and control of the keys, and thus, to a large extent, controls and tracks the vehicles to which the keys provide access.
While the Key Track system described above has proven extremely valuable in the tracking and control of keys, it nevertheless has certain problems and shortcomings inherent in its design. For example, the backplane of the system, which may contain dozens of upstanding metal contacts for engaging the electronic touch memory devices of key cards, can be relatively complex and labor intensive to fabricate and requires precision in the placement and orientation of contact pairs. In addition, foreign items such as loose keys or other small metal items that may inadvertently be dropped into or hang through one of the slots in the top panel can and sometimes do short the contacts on the backplane, resulting in the potential for false key tracking logs or, in extreme cases, error conditions that can result in degradation of the integrity of the entire system. Furthermore, because the reading of the codes stored in the touch memory devices relies upon physical contact between the touch memory devices and the electrical contacts on the backplane, resistances that can result from corroded contacts or dirty touch memory devices can also result in false and degrading readings. Additionally, the electrical contacts sometimes become bent or sprung so that they fail to make proper contact with the touch memory devices of key cards placed in their corresponding slots. These and other related problems all result from the requirement in the Key Track system that object detection and identification relies upon physical electrical contact between a set of electrical contacts and an electronic touch memory device.
Thus, even though the Key Track system has proven very useful and successful, there exists a continuing need to enhance the system in such a way that the problems mentioned above are addressed in an efficient, economic, and reliable way. It is to the provision of such enhancements and improvements that the present invention is primarily directed.